Converting audio files? Options

[killthishype.]

Hi guys, not sure if it's the right forum to post at, but here goes.

Have got like 2k songs in different formats (MP3/AAC etc.) with bitrates ranging from 192-320kbps; some were previously converted by the iTunes encoder, e.g. from 192kbps to a higher bitrate (took me until today to realize it's pointless)

I understand that converting a lossy format to another lossy one would result in a loss of details, but I still hope to consolidate all of my songs to a similar format and bitrate (e.g. all songs in AAC format at 256kbps). Or should I just leave it?

Also, should I continue using the iTunes encoder or switch over to LAME instead?

Any form of advice would be greatly appreciated, thanks!

[SonicBooom!]

For portable purposes, I think it's much better to convert 320kbps MP3 to 256kbps AAC, but converting an mp3 below 256kbps to 256kbps? Yeah, it's pointless indeed. You're making the file bigger while lowering it's quality in every conversion. Can't hear any difference between AAC and MP3 in 320kbps, but try testing them in 64kbps and know why I prefer AAC